/*
* Copyright (C) 2011 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
* in compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.common.collect;
import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import java.io.Serializable;
import java.util.NoSuchElementException;
import java.util.Set;
import javax.annotation.Nullable;
/**
* An empty contiguous set.
*
* @author Gregory Kick
*/
@GwtCompatible(emulated = true)
@SuppressWarnings("unchecked") // allow ungenerified Comparable types
final class EmptyContiguousSet<C extends Comparable> extends ContiguousSet<C> {
EmptyContiguousSet(DiscreteDomain<C> domain) {
super(domain);
}
@Override public C first() {
throw new NoSuchElementException();
}
@Override public C last() {
throw new NoSuchElementException();
}
@Override public int size() {
return 0;
}
@Override public ContiguousSet<C> intersection(ContiguousSet<C> other) {
return this;
}
@Override public Range<C> range() {
throw new NoSuchElementException();
}
@Override public Range<C> range(BoundType lowerBoundType, BoundType upperBoundType) {
throw new NoSuchElementException();
}
@Override ContiguousSet<C> headSetImpl(C toElement, boolean inclusive) {
return this;
}
@Override ContiguousSet<C> subSetImpl(
C fromElement, boolean fromInclusive, C toElement, boolean toInclusive) {
return this;
}
@Override ContiguousSet<C> tailSetImpl(C fromElement, boolean fromInclusive) {
return this;
}
//Abstract method doesn't exist in GWT emulation
/* @Override */ int indexOf(Object target) {
return -1;
}
@Override public UnmodifiableIterator<C> iterator() {
return Iterators.emptyIterator();
}
@Override boolean isPartialView() {
return false;
}
@Override public boolean isEmpty() {
return true;
}
@Override public ImmutableList<C> asList() {
return ImmutableList.of();
}
@Override public String toString() {
return "[]";
}
@Override public boolean equals(@Nullable Object object) {
if (object instanceof Set) {
Set<?> that = (Set<?>) object;
return that.isEmpty();
}
return false;
}
@Override public int hashCode() {
return 0;
}
@GwtIncompatible("serialization")
private static final class SerializedForm<C extends Comparable> implements Serializable {
private final DiscreteDomain<C> domain;
private SerializedForm(DiscreteDomain<C> domain) {
this.domain = domain;
}
private Object readResolve() {
return new EmptyContiguousSet<C>(domain);
}
private static final long serialVersionUID = 0;
}
@GwtIncompatible("serialization")
@Override
Object writeReplace() {
return new SerializedForm<C>(domain);
}
}
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